EP4310416A1

EP4310416A1 - Hybrid multi-air conditioning system

Info

Publication number: EP4310416A1
Application number: EP23186282.2A
Authority: EP
Inventors: Yejin Kim; Eunjun Cho; Woojoo Choi; Jihyeong RYU; Dongkeun Yang
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2022-07-22
Filing date: 2023-07-19
Publication date: 2024-01-24
Also published as: CN117433075A; KR20240013558A; US20240027077A1

Abstract

The present disclosure relates to a hybrid multi-air conditioning system.The hybrid multi-air conditioning system of the present disclosure includes a hot water supply unit including a hot water supply heat exchanger for exchanging heat between the refrigerant and water accommodated in the water tank and a first hot water supply expansion valve for blocking or flowing the refrigerant condensed from the hot water supply heat exchanger; at least one indoor device installed indoors and including an indoor heat exchanger and an indoor expansion valve; an outdoor device connected to the indoor device and the hot water supply unit through a refrigerant pipe and including an outdoor heat exchanger, a compressor, and an outdoor expansion valve; a second hot water supply discharge pipe having one side branched from the first hot water supply discharge pipe connecting the hot water supply heat exchanger and the indoor heat exchanger and the other side joining the first discharge pipe connecting the compressor and the outdoor heat exchanger; and a second hot water supply expansion valve installed on the second hot water supply discharge pipe.

Description

The Background

The present specification relates to a hybrid multi-air conditioning system. More specifically, the present specification relates to a hybrid multi-air conditioning system including a water tank heat exchanger and a control method thereof.
In general, a hybrid system capable of simultaneous cooling and hot water supply operation uses a plate heat exchanger such as a hydro-kit when using a water tank to firstly perform refrigerant-water heat exchange with the air-side cycle, and to secondly perform water-water heat exchange between the hydro-kit and the water tank.
As a prior art, Korean Patent Publication No. 1 0-2010-0023877 discloses a heat pump type hot water supply device.
When using a hydro-kit as in the prior art, the amount of condensation heat on the refrigerant side can be controlled by the flow rate of water. However, if the refrigerant-side condensation heat exchanger is directly wound around the water tank, the condensation heat amount varies according to the water temperature inside the water tank and the user's water consumption, so the control point of the water tank condenser changes.
In addition, when the receiver is installed in the condenser, only the low-pressure liquid refrigerant is sent to the evaporator, so that a sudden drop in low pressure can be prevented by the expansion valve of the indoor device during cooling operation.
In the case of a hybrid system capable of simultaneous hot water supply and cooling operation, the water tank and the outdoor device side heat exchanger are operated by a condenser and are divided into two, and expansion valves are installed at the water tank outlet and the outdoor device outlet, respectively, and refrigerant is sent to the indoor device-side expansion valve. The refrigerant discharged from each condenser must pass through two expansion valves until the refrigerant is changed from high pressure to low pressure, wherein if the opening of the expansion valve is too small, excessive pressure loss occurs and two-phase refrigerant enters the expansion valve.
When a two-phase refrigerant enters the expansion valve, the evaporation temperature of the evaporator is greatly reduced, and the evaporation temperature reduction may cause cycle hunting and limit control entry.
In addition, in the case of the conventional hybrid multi-air conditioning system, there is a problem of damage to the compressor due to an increase in the condensation temperature on the water tank side and a decrease in cooling capacity due to a reduction in the frequency of the compressor.
In addition, since the degree of supercooling at the water tank side was not secured, a two-phase refrigerant other than liquid refrigerant flowed into the indoor device, resulting in insufficient cooling capacity and excessive drop in low pressure.

The Summary

A first problem to be solved by the present disclosure is to provide a hybrid multi-air conditioning system in which a heat exchanger for heating a water tank and a heat exchanger for an outdoor device are disposed in series to increase the flow rate of refrigerant in the superheating degree section, thereby securing hot water supply performance.
In addition, a second problem of the present disclosure is to provide a hybrid multi-air conditioning system capable of more stably realizing a cycle and lowering a condensation temperature by securing supercooling of a heat exchanger for an outdoor device.
A third problem of the present disclosure is to provide a hybrid multi-air conditioning system capable of operating only a heat exchanger for a water tank as a condenser or operating only a heat exchanger for an outdoor device as a condenser.
In addition, a fourth problem of the present disclosure is to provide a hybrid multi-air conditioning system in which a water tank can firstly perform heat exchange by directly exchanging heat between a refrigerant and water.
In addition, the fifth problem of the present disclosure is to provide a hybrid multi-air conditioning system that can prevent two-phase refrigerant from entering by adjusting the opening of the first hot water supply expansion valve and the outdoor expansion valve without installing a separate receiver and thus controlling the optimal degree of supercooling.
In addition, a sixth problem of the present disclosure is to provide a hybrid multi-air conditioning system capable of simultaneous operation of hot water supply and cooling as well as operation of hot water supply and heating.
In order to solve the above problems, a multiple air conditioning system of the present disclosure includes a hot water supply unit including a hot water supply heat exchanger for exchanging heat between the refrigerant and water accommodated in the water tank and a first hot water supply expansion valve for blocking or flowing the refrigerant condensed from the hot water supply heat exchanger; at least one indoor device installed indoors and including an indoor heat exchanger and an indoor expansion valve; and an outdoor device connected to the indoor device and the hot water supply unit through a refrigerant pipe and including an outdoor heat exchanger, a compressor, and an outdoor expansion valve.
In addition, the multiple air conditioning system may include a second hot water supply discharge pipe having one side branched from the first hot water supply discharge pipe connecting the hot water supply heat exchanger and the indoor heat exchanger and the other side joining the first discharge pipe connecting the compressor and the outdoor heat exchanger.
In addition, the multiple air conditioning system may include a second hot water supply expansion valve installed on the second hot water supply discharge pipe.
In addition, the hybrid multi-air conditioning system may further include a first temperature sensor installed to detect the water temperature in the water tank.
In addition, the hybrid multi-air conditioning system may further include a second temperature sensor installed at a rear end of the compressor.
In addition, the hybrid multi-air conditioning system may further include a first pressure sensor installed at the rear end of the compressor.
In addition, the hot water supply heat exchanger may wind the outer wall of the water tank in a coil form and may exchange heat between the refrigerant and water while the refrigerant flows into the inside of the hot water supply heat exchanger.
In addition, the outdoor device may include a hot water supply valve for flowing the compressed refrigerant from the compressor to the hot water supply unit; and a discharge valve for flowing the compressed refrigerant from the compressor to the outdoor heat exchanger or the indoor heat exchanger.
In addition, the outdoor device may further include a four-way valve for transferring the refrigerant passing through the discharge valve to the outdoor heat exchanger or to the indoor heat exchanger.
In addition, a plurality of indoor heat exchangers may be provided, and each indoor heat exchanger may be connected in parallel.
In addition, a first hot water supply expansion valve may be installed at a rear end of a branch point of the second hot water supply discharge pipe in the first hot water supply discharge pipe.
In addition, in the hot water supply and cooling operation mode, either the hot water supply heat exchanger or the outdoor heat exchanger may operate as a condenser, or the hot water supply heat exchanger and the outdoor heat exchanger may operate as a condenser.
In addition, in the hot water supply and cooling operation mode, one of the first hot water supply expansion valve and the second hot water supply expansion valve may be opened and the other may be blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or less and when the cooling load is lower than the reference value, the first hot water supply expansion valve may be opened and the second hot water supply expansion valve may be blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or less and, when the cooling load is lower than the reference value, only the hot water supply heat exchanger may operate as a condenser.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or less and, when the cooling load is higher than the reference value, the second hot water supply expansion valve may be opened and the first hot water supply expansion valve may be blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or less and, when the cooling load is higher than the reference value, the hot water supply heat exchanger and the outdoor heat exchanger may operate as condensers.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or more and, when the cooling load is higher than the reference value, the second hot water supply expansion valve may be opened and the first hot water supply expansion valve may be blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or more and, when the cooling load is higher than the reference value, the hot water supply heat exchanger and the outdoor heat exchanger may operate as condensers.
In addition, in the hot water supply and cooling operation mode, even if the temperature of the water accommodated in the water tank is the reference temperature or more and, when the cooling load is higher than the reference value, the first hot water supply expansion valve may be opened or the second hot water supply expansion valve may be opened according to the discharge the superheating degree of the compressor.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or more and, when the cooling load is lower than the reference value, only the outdoor heat exchanger may operate. as a condenser.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank is the reference temperature or more and, when the cooling load is lower than the reference value, the water tank may be heated by a separate heater.
Details of other embodiments are included in the detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram illustrating a hybrid multi-air conditioning system according to an embodiment of the present disclosure.
FIG. 2 is a detailed configuration diagram illustrating a hybrid multi-air conditioning system according to an embodiment of the present disclosure of FIG. 1.
FIG. 3 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during independent cooling operation.
FIG. 4 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during independent heating operation.
FIG. 5 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during independent operation of hot water supply.
FIG. 6 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during heating and hot water supply operation.
FIG. 7 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during cooling and hot water supply operations.
FIG. 8 is an operation diagram illustrating a state where only the hot water supply heat exchanger operates as a condenser during cooling and hot water supply operations of the hybrid multi-air conditioning system of FIG. 2.
FIG. 9 is a configuration diagram illustrating a hybrid multi-air conditioning system according to another embodiment of the present disclosure of FIG. 1.
FIG. 10 is a flowchart illustrating a method for controlling a hybrid multi-air conditioning system according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

The features of the present disclosure will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in a variety of different forms.
Hereinafter, with reference to the accompanying drawings, the preferred embodiments of the present disclosure are described as follows.
FIG. 1 is a schematic configuration diagram illustrating a hybrid multi-air conditioning system according to an embodiment of the present disclosure, and FIG. 2 is a detailed configuration diagram illustrating a hybrid multi-air conditioning system according to an embodiment of the present disclosure of FIG. 1.
Referring to FIGS. 1 and 2, the hybrid multi-air conditioning system 100 according to an embodiment of the present disclosure includes a hot water supply unit 30, at least one indoor device 20 for both heating and cooling, and a outdoor device 10 for both heating and cooling.
The hot water supply unit 30 consists of a water tank 31 that is long in the vertical direction while storing water for hot water supply, a water circulation pipe supplying water from the outside to the bottom of the water tank 31 and discharging the heated water to the outside through the top of the water tank 310, and a hot water supply heat exchanger 32 attached to the outside of the water tank 31 and coupled to enable heat dissipation.
At this time, the heat exchange between the water tank 31 and the hot water supply heat exchanger 32 is performed by heat exchange between the refrigerant flowing through the hot water supply heat exchanger 32 and the water inside the water tank 31, and the hot water supply heat exchanger 32 acts as a condenser that performs a heat dissipation function.
In the hot water supply heat exchanger 32, the pipe through which the refrigerant flows directly winds the outer wall of the water tank 31 in a coil shape to increase the contact area, thereby exchanging heat. In addition, the hot water supply heat exchanger 32 has a hot water supply input pipe 34 connected to the second discharge pipe 42 of the outdoor device 10 and a first hot water supply discharge pipe 35 flowing the condensed liquid refrigerant after heat exchange with the water tank 31.
The first hot water supply discharge pipe 35 is connected to a first node n1 connecting the indoor device 20, the outdoor device 10, and the hot water supply unit 10. A first hot water supply expansion valve 33 may be disposed in the first hot water supply discharge pipe 35 of the hot water supply heat exchanger 32.
The first hot water supply expansion valve 33 formed in the discharge portion of the hot water supply heat exchanger 32 may be an electronic expansion valve, adjusts the flow rate of the refrigerant flowing through the pipe of the hot water supply heat exchanger 32, and flows the condensed refrigerant into the outdoor device 10 or the indoor device 20.
In this way, heat exchange is performed directly between the water and the refrigerant in the water tank 31 without a separate hydro kit and thus the heat exchange takes place directly, so that the heat exchange efficiency can be improved.
Meanwhile, the indoor device 10 for both heating and cooling includes a compressor 13, an outdoor heat exchanger 11, an outdoor heat exchanger fan 12, and a switching means. Here, the switching means includes a four-way valve 14. The compressor 13 may include a plurality of compressors 13 connected in parallel, but is not limited thereto. An accumulator may be formed at the input end of the compressor 13. When there are a plurality of compressors 13, the first compressor may be an inverter compressor capable of varying the compression capacity of the refrigerant, and the second compressor may be a constant speed compressor having a constant compression capacity of the refrigerant.
The low-pressure connection pipe 46 connected to the indoor device 20 is connected to the input pipe 45 of the compressor 13 via the four-way valve 14.
The first and second discharge pipes 42 and 43 are connected to the discharge portion 41 of the compressor 13 as a high-pressure connection pipe. The first discharge pipe 43 flows the discharged high-temperature and high-pressure gaseous refrigerant into the outdoor heat exchanger 11. The second discharge pipe 42 flows the discharged high-temperature and high-pressure gaseous refrigerant into the hot water supply unit 30 and is connected to the hot water supply heat exchanger 32.
The first discharge pipe 43 passes through the four-way valve 14 and is connected to the outdoor heat exchanger 11. The second discharge pipe 42 bypasses the refrigerant discharged from the compressor 13 without passing through the four-way valve 14 and is connected to the hot water supply heat exchanger 32.
The outdoor heat exchanger 11 is connected to the four-way valve 14 through the first discharge pipe 43. In the outdoor heat exchanger 11, the refrigerant is condensed or evaporated by heat exchange with outdoor air. At this time, in order to facilitate heat exchange, the outdoor device fan 12 introduces air into the outdoor heat exchanger 11. In the hybrid multi-air conditioning system 100 capable of heating and cooling and hot water supply, the outdoor heat exchanger 11 is used as a condenser during cooling operation, and the outdoor heat exchanger 11 is used as an evaporator during heating operation.
An outdoor expansion valve 17 is installed on the liquid pipe connection pipe 44 connecting the outdoor heat exchanger 11 and the indoor device. The outdoor expansion valve 17 expands the refrigerant during heating operation. The outdoor expansion valve 17 expands the refrigerant condensed in the plurality of indoor heat exchangers 21 during heating operation before flowing into the outdoor heat exchanger 11.
The four-way valve 14 is provided in the discharge portion 41 of the compressor 13 and switches the flow path of the refrigerant flowing in the outdoor device 10. The four-way valve 14 properly switches the flow path of the refrigerant discharged from the compressor 13 according to the hot water supply, cooling and heating operation of the hybrid multi-air conditioning system 100.
Such an outdoor device 10 for both heating and cooling includes a hot water supply valve 15 between the second discharge pipe 42 and the hot water supply input pipe 34 and includes a discharge valve 16 between the first discharge pipe 43 and the discharge portion 41 of the compressor 13.
The hot water supply valve 15 and the discharge valve 16 may be solenoid valves that selectively operate to block or flow the refrigerant as needed.
The hot water supply valve 15 and the discharge valve 16 do not need to operate the hot water supply operation when the water temperature reaches the user's desired water temperature during cooling and hot water supply and heating and hot water supply operations. In addition, when the hot water valve 15 is closed, only the outdoor device 10 serves as a condenser during cooling operation, and only the indoor device 20 serves as a condenser during heating operation.
Meanwhile, the outdoor device 10 may further include a supercooling device (not illustrated) on the liquid pipe connection pipe 44, and the supercooling device cools the refrigerant transferred to the indoor device 20 during cooling operation.
Meanwhile, the hybrid multi-air conditioning system 100 includes at least one indoor device 20.
A plurality of indoor devices 20 for both heating and cooling may be connected to one outdoor device 10, and three indoor devices B1, B2, and B3 are illustrated in FIGS. 1 and 2, but the present disclosure is not limited thereto.
Each of the indoor devices B1, B2, and B3 for both heating and cooling includes an indoor heat exchanger 21, an indoor expansion valve 22, and an indoor fan 23, respectively, and as illustrated in FIG. 2, when three indoor devices B1, B2, and B3 are installed, the first, second, and third indoor heat exchangers 21, the first, second, and third indoor expansion valves 22 and the first, second, and third indoor device fans 23 are included. The first, second, and third indoor expansion valves 22 are installed on the first, second, and third indoor connection pipes 26 connecting the first, second, and third indoor heat exchangers 21 and the first node n1. The first, second, and third indoor connection pipes 26 are connected to the liquid pipe connection pipe 44 of the outdoor device 10 at the first node n1.
Each of the indoor devices B1, B2, and B3 for both cooling and heating may be connected in parallel.
Each of the indoor devices B1, B2, and B3 for both cooling and heating may be connected in series.
The first, second, and third indoor devices B1, B2, and B3 for both cooling and heating are also installed with low-pressure connection pipes 46 through which the discharged refrigerant flows to the compressor 13.
The air conditioning system 100 according to the present embodiment may further include a pressure sensor for measuring the pressure of the refrigerant, a temperature sensor for measuring the temperature of the refrigerant, and a strainer for removing foreign substances present in the refrigerant flowing through the refrigerant pipe.
In the hybrid multi-air conditioning system 100 of the present disclosure, when the outdoor device 10, the indoor device 20, and the hot water supply unit 30 act as condensers or evaporators according to operation modes, a separate refrigerant flow rate control device is not applied and it can be performed by opening the currently installed electronic expansion valve. In particular, the optimum refrigerant flow rate control is possible by controlling each electronic expansion valve by determining the superheating degree or supercooling degree through a plurality of temperature sensors formed in each electronic expansion valve.
Specifically, in the hybrid multi-air conditioning system 100 of the present disclosure, the temperature control of the hot water supply unit 30 is performed in a state where the amount of water cannot be controlled, and direct heat exchange is performed without a separate hydro kit, so that it is possible to determine whether two-phase refrigerant flows into the evaporator by determining the superheating degree of the discharged refrigerant. Therefore, it is possible to block the two-phase refrigerant by controlling the opening of the first hot water supply expansion valve 33 according to whether the two-phase refrigerant flows in.
The hybrid multi-air conditioning system 100 according to an embodiment of the present disclosure is capable of independent cooling operation, independent heating operation, cooling and hot water supply operation, heating and hot water supply operation, and independent hot water supply operation.
In addition, during cooling and hot water supply operations, a heat exchanger operating as a condenser may be variously set according to the temperature of the water in the water tank 31 and the cooling load.
During cooling operation, the outdoor heat exchanger 11 operates as a condenser.
In addition, for hot water heating, the hot water supply heat exchanger 32 also operates as a condenser.
At this time, in order to increase cooling and hot water supply efficiency and prevent damage to the compressor, the outdoor heat exchanger 11 or the hot water supply heat exchanger 32 operating as a condenser may be selected according to each situation.
To this end, a hot water supply discharge pipe 36 having one side which is branched from the first hot water supply discharge pipe 35 connecting the hot water supply heat exchanger 32 and the indoor heat exchanger 21, and the other side which is joined to the first discharge pipe 43 connecting the compressor 13 and the outdoor heat exchanger 11, and a second hot water supply expansion valve 37 installed on the second hot water discharge pipe 36 are included.
In detail, the second hot water supply discharge pipe 36 may be branched from the first hot water supply discharge pipe 35 between the hot water supply heat exchanger 32 and the first hot water supply expansion valve 33 and may be joined to the first discharge pipe 43 between the four-way valve 14 and the outdoor heat exchanger 11.
In addition, a first temperature sensor 38 installed to detect the temperature of the water in the water tank 31 may be further included.
In addition, a second temperature sensor 47 installed at a rear end (discharge end) of the compressor 13 to measure the temperature of the refrigerant may be further included.
In addition, a first pressure sensor 48 installed at a rear end (discharge end) of the compressor 13 to measure the pressure of the refrigerant may be further included.
The condensation temperature can be predicted through the high-pressure information detected by the first pressure sensor 48.
Hereinafter, the operation of the system according to each driving mode will be described in detail.
FIG. 3 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during independent cooling operation.
Referring to FIG. 3, since the hot water supply operation is stopped during the cooling-only operation, only the outdoor heat exchanger 11 singly operates as a condenser.
At this time, the hot water supply valve 15 is blocked and the discharge valve 16 is opened. Then, the first hot water supply expansion valve 33 and the second hot water supply expansion valve 37 are blocked, and the outdoor expansion valve 17 and the indoor expansion valve 22 are opened.
For reference, when a plurality of indoor expansion valves 22 are provided, only a portion of the indoor expansion valves 22 may be opened or the entire indoor expansion valve 22 may be opened according to the indoor environment.
Specifically, the refrigerant, which becomes a high-temperature and high-pressure gaseous phase after the compressor 13 operates, passes through the discharge valve 16 and then passes through the four-way valve 14 to be sent to the outdoor heat exchanger 11. The high-pressure, high-temperature gaseous refrigerant sent to the outdoor heat exchanger 11, as described above, is condensed into a high-pressure liquid refrigerant by exchanging heat with outdoor air.
The condensed liquid refrigerant passes through the outdoor expansion valve 17, passes through the indoor expansion valve 22 of the indoor device 20 operating in a cooling operation at the first node n1 to be expanded, and then is transferred to the indoor heat exchanger 21 operating as the evaporator as a low-pressure refrigerant.
After the low-pressure refrigerant enters the indoor device 20, the low-pressure refrigerant is evaporated through heat exchange with indoor air. Thus the indoor is cooled. Then, the low-temperature gaseous refrigerant discharged from the indoor heat exchanger 21 repeats the process of passing through the four-way valve 14 through the low-pressure connection pipe 46, flows into the input pipe 45 of the compressor 13, and being introduced into the compressor 13 again, and being re-discharged as a high-pressure, high-temperature gaseous refrigerant.
At this time, the outdoor expansion valve 17 is fully open, and the indoor expansion valve 22 can adjust the opening degree according to the target indoor temperature and the cooling load.
Through this process, indoor cooling may proceed in a state where hot water supply is stopped.
FIG. 4 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during independent heating operation.
Referring to FIG. 4, in case of independent heating operation, the hot water supply operation is stopped, and the outdoor heat exchanger 11 operates as an evaporator. In addition, the indoor heat exchanger 21 operates as a condenser.
At this time, the hot water supply valve 15 is blocked and the discharge valve 16 is opened. Then, the first hot water supply expansion valve 33 and the second hot water supply expansion valve 37 are blocked, and the outdoor expansion valve 17 and the indoor expansion valve 22 are opened.
For reference, when a plurality of indoor expansion valves 22 are provided, only some of the indoor expansion valves 22 may be opened according to the indoor environment, and all of the indoor expansion valves 22 may be opened.
Specifically, the refrigerant, which becomes a high-temperature and high-pressure gaseous phase after the compressor 13 operates, passes through the discharge valve 16 and then the passes through four-way valve 14 to be sent to the indoor heat exchanger 21. The high-pressure, high-temperature gaseous refrigerant sent to the indoor heat exchanger 21, as described above, is condensed into a high-pressure liquid refrigerant through heat exchange with indoor air. In this process, the heating of the indoor proceeds.
The condensed high-pressure liquid refrigerant passes through the indoor expansion valve 22 and is sent to the side of the outdoor expansion valve 17 at the first node n1. In addition, the low-temperature two-phase refrigerant passing through the outdoor expansion valve 17 is transferred to the outdoor heat exchanger 11 operating as an evaporator.
The low-temperature two-phase refrigerant introduced into the outdoor heat exchanger 11 exchanges heat with outdoor air and evaporates into a low-temperature gaseous refrigerant. Thereafter, the low-temperature gaseous refrigerant discharged from the outdoor heat exchanger 11 repeats the process of passing through the four-way valve 14, flows into the input pipe 45 of the compressor 13, and being introduced into the compressor 13 again, and being re-discharged as the high-pressure and high-temperature gaseous refrigerant.
At this time, the outdoor expansion valve 17 is fully open, and the indoor expansion valve 22 can adjust the opening degree thereof according to the target indoor temperature and heating load.
Through this process, in a state where hot water supply is stopped, indoor heating may proceed.
FIG. 5 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during independent operation of hot water supply.
The independent hot water supply operation is performed when only hot water supply is requested without cooling or heating.
At this time, the hot water supply valve 15 is opened and the discharge valve 16 is blocked. In addition, the first hot water supply expansion valve 33 and the outdoor expansion valve 17 are opened, and the second hot water supply expansion valve 37 and the indoor expansion valve 22 are blocked.
Specifically, the refrigerant that becomes a high-pressure gaseous phase after the compressor 13 operates is sent to the hot water supply heat exchanger 32 operating as a condenser through the second discharge pipe 42 and the hot water supply valve 15. The high-temperature, high-pressure gaseous refrigerant sent to the hot water supply heat exchanger 32, as described above, exchanges heat with the water inside the water tank 31 to heat the water inside the water tank 31 and is condensed into a high-pressure liquid phase.
The condensed high-pressure liquid refrigerant passes through the first hot water supply expansion valve 33 and is transferred from the first node n1 to the outdoor expansion valve 17 side. Then, the refrigerant expanded into the low-temperature two-phase refrigerant in the outdoor expansion valve 17 repeats the process of passing through the outdoor heat exchanger 11 operating as an evaporator, passing through the four-way valve 14, and flowing into the input pipe 45 of the compressor 13, being introduced into the compressor 13 again, and being re-discharged as a high-pressure, high-temperature gaseous refrigerant.
Through this process, only hot water supply operation may be performed in a state where indoor cooling or heating is stopped.
FIG. 6 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during heating and hot water supply operation.
When heating and hot water operation is requested, all valves except for the second hot water supply expansion valve 37 are opened. In other words, the second hot water supply expansion valve 37 is blocked, the hot water supply valve 15 and the discharge valve 16 are opened, and the first hot water supply expansion valve 33, the outdoor expansion valve 17, and the indoor expansion valve 22 are open.
In addition, the outdoor heat exchanger 11 operates as an evaporator, and the indoor heat exchanger 21 operates as a condenser.
For reference, when a plurality of indoor expansion valves 22 are provided, only some of the indoor expansion valves 22 may be opened according to the indoor environment, and all of the indoor expansion valves 22 may be opened.
Specifically, after the compressor 13 operates, a portion of the high-temperature and high-pressure gaseous refrigerant passes through the discharge valve 16 and then passes through the four-way valve 14 and is sent to the indoor heat exchanger 21, and the remaining portion passes through the hot water supply valve 15 and is sent to the hot water supply heat exchanger 32. The high-pressure, high-temperature refrigerant sent to the outdoor heat exchanger 11 and the hot water supply heat exchanger 32, as described above, is condensed into a high-pressure liquid refrigerant while exchanging heat with the indoor air to heat the indoor, or exchanges heat with water inside the water tank 31 to heat the water inside the water tank 31 and is condensed into a high-pressure liquid refrigerant.
The condensed high-pressure liquid refrigerant passes through the indoor expansion valve 22 and the first hot water supply expansion valve 33, respectively, meets at the first node n1 and is transferred to the outdoor heat exchanger 11 through the outdoor expansion valve 17 of the outdoor device 10 which operates as an evaporator at the first node n1.
The refrigerant introduced into the outdoor heat exchanger 11 repeats the process of being evaporated by heat exchange with outdoor air, passing through the four-way valve 14 through the first discharge pipe 43, and then flowing to the input pipe 45 of the compressor 13, being introduced into the compressor 13 again, and being re-discharged as a high-pressure, high-temperature gaseous refrigerant.
At this time, the indoor expansion valve 22 may adjust the opening degree according to the target indoor temperature and the heating load.
Through this process, hot water supply operation and indoor heating can be performed simultaneously.
FIG. 7 is an operation diagram illustrating the hybrid multi-air conditioning system of FIG. 2 during cooling and hot water supply operations.
When cooling and hot water supply operations of the hybrid multi-air conditioning system according to an embodiment of the present disclosure start, the flow of refrigerant proceeds as illustrated in FIG. 7.
When the cooling and hot water supply operation starts, the heat exchangers 11 and 32 of the outdoor device 10 and the hot water supply unit 30 operate as condensers, and the heat exchanger 21 of the indoor device 20 operates as an evaporator.
When cooling and hot water supply operation is requested, all valves except for the first hot water supply expansion valve 33 are opened. In other words, the first hot water supply expansion valve 33 is blocked, the hot water supply valve 15 and the discharge valve 16 are opened, and the second hot water supply expansion valve 37, the outdoor expansion valve 17, and the indoor expansion valve 22 is open.
For reference, when a plurality of indoor expansion valves 22 are provided, only some of the indoor expansion valves 22 may be opened according to the indoor environment, and all of the indoor expansion valves 22 may be open.
Specifically, a portion of the refrigerant that has become a high-pressure gaseous phase after the compressor 13 operates passes through the discharge valve 16 and then passes through the four-way valve 14 and is sent to the outdoor heat exchanger 11, and the remaining part passes through the hot water supply valve 15 and is sent to the hot water supply heat exchanger 32. The high-pressure, high-temperature refrigerant sent to the outdoor heat exchanger 11 and the hot water supply heat exchanger 32, as described above, is either condensed by heat exchange with outdoor air, or is condensed into a liquid phase by heat exchange with the water inside the water tank 31 to heat water inside the water tank 31.
The condensed liquid refrigerant passes through the outdoor expansion valve 17 and the first hot water supply expansion valve 33, respectively, meets at the first node n1, passes through the indoor expansion valve 22 of the indoor device 20 which operates in cooling mode at the first node n1, and thus is transferred to the indoor heat exchanger 21 as the low-pressure refrigerant.
After entering the indoor device 20, the low-pressure refrigerant evaporates by exchanging heat with indoor air, passes through the four-way valve 14 through the low-pressure connection pipe 46 while cooling the indoor air, and enters the input pipe 45 of the compressor 13 and is introduced into the compressor 13 again.
In the case of the present disclosure, in the hot water supply and cooling operation mode, through at least one information of the water temperature detected by the first temperature sensor 38, the refrigerant discharge temperature detected by the second temperature sensor 47, and the discharge pressure and the condensation temperature detected by the first pressure sensor 48, it is possible to select the outdoor heat exchanger 11 or the hot water supply heat exchanger 32.
In addition, the outdoor heat exchanger 11 or the hot water supply heat exchanger 32 to be used as the condenser can be selected through the operating frequency (Hz) of the compressor 13.
At this time, only the outdoor heat exchanger 11 may singly operate as a condenser.
In addition, only the hot water supply heat exchanger 32 may singly operate as a condenser.
In addition, both the outdoor heat exchanger 11 and the hot water supply heat exchanger 32 may operate as condensers.
For example, when only the outdoor heat exchanger 11 is singly operated as a condenser, the hot water supply valve 15 is blocked and the discharge valve 16 is opened, similarly to the independent cooling operation. Then, the first hot water supply expansion valve 33 and the second hot water supply expansion valve 37 are blocked, and the outdoor expansion valve 17 and the indoor expansion valve 22 are opened.
At this time, even in the cooling and hot water supply operation, only the outdoor heat exchanger 11 operates as a condenser.
Specifically, the refrigerant, which has become a high-pressure gaseous phase after the compressor 13 operates, passes through the discharge valve 16 and then passing through the four-way valve 14 to be sent to the outdoor heat exchanger 11. The high-pressure, high-temperature refrigerant sent to the outdoor heat exchanger 11, as described above, is condensed through heat exchange with outdoor air.
The condensed liquid refrigerant passes through the outdoor expansion valve 17 and passes through the indoor expansion valve 22 of the indoor device 20 performing a cooling operation at the first node n1 and then is transferred to the indoor heat exchanger 21 as the low-pressure refrigerant.
After entering the indoor device 20, the low-pressure refrigerant repeats a process of evaporating by exchanging heat with indoor air, passing through the four-way valve 14 through the low-pressure connection pipe 46 while cooling the indoor air, and flowing into the input pipe 45 of the compressor 13, being introduced into the compressor 13 again, and being re-discharged as a high-pressure, high-temperature gaseous refrigerant.
FIG. 8 is an operation diagram illustrating a state where only the hot water supply heat exchanger operates as a condenser during cooling and hot water supply operations of the hybrid multi-air conditioning system of FIG. 2.
As another example, when only the hot water supply heat exchanger 31 singly operates as a condenser, the flow of refrigerant proceeds as illustrated in FIG. 8.
In other words, the hot water supply valve 15 is opened and the discharge valve 16 is blocked. In addition, the first hot water supply expansion valve 33 and the indoor expansion valve 22 are opened, the second hot water supply expansion valve 33 and the outdoor expansion valve 17 are blocked, and only the hot water supply heat exchanger 32 operates as a condenser.
For reference, when a plurality of indoor expansion valves 22 are provided, only some of the indoor expansion valves 22 may be opened according to the indoor environment, and all of the indoor expansion valves 22 may be opened.
Specifically, the refrigerant, which has become a high-pressure gas phase after the compressor 13 operates, is sent to the hot water supply heat exchanger 32 operating as a condenser through the second discharge pipe 42 and the hot water supply valve 15. The high-temperature, high-pressure gaseous refrigerant sent to the hot water supply heat exchanger 32, as described above, exchanges heat with the water inside the water tank 31 to heat the water inside the water tank 31 and is condensed into a high-pressure liquid phase.
The condensed high-pressure liquid refrigerant passes through the second hot water supply expansion valve 37 and is transferred from the first node n1 to the indoor expansion valve 22 side. Then, the refrigerant that has passed through the indoor expansion valve 22 repeats the process of passing through the indoor heat exchanger 11, passing through the four-way valve 14, flowing into the input pipe 45 of the compressor 13, being introduced into the compressor 13, again, and being re-discharged as a high-pressure, high-temperature gaseous refrigerant.
Through this process, even during cooling and hot water supply operations, only hot water supply operation may be performed singly. In other words, only the hot water supply heat exchanger 32 can operate as a condenser.
FIG. 9 is a configuration diagram illustrating a hybrid multi-air conditioning system according to another embodiment of the present disclosure of FIG. 1.
The hybrid multi-air conditioning system according to the present disclosure includes a controller 50.
The controller 50 may receive values measured from the first temperature sensor 38, the second temperature sensor 47, and the first pressure sensor 48.
In other words, the controller 50 may receive the water temperature measured by the first temperature sensor 38, the discharge temperature measured by the second temperature sensor 47, the discharge pressure measured by the first pressure sensor 48, or condensation temperature value according to this.
For reference, the controller 50 can calculate the discharge superheating degree based on the discharge temperature measured by the second temperature sensor 47, the discharge pressure measured by the first pressure sensor 48, or the condensation temperature value according to this.
In addition, the controller 50 may receive operation frequency (Hz) information of the compressor.
In addition, the controller 50 can open and close a hot water supply valve 15, a discharge valve 16, a first hot water supply expansion valve 33, a second hot water supply expansion valve 37, an outdoor expansion valve 17, and an indoor expansion valve 22 or can adjust the opening degree thereof.
In addition, the controller 50 may adjust the open position of the four-way valve 14, and may adjust whether or not the respective fans 12 and 23 operate and the number of revolutions per unit time.
In addition, the controller 50 may control whether or not the heater 60 to be described later operates and the output thereof.
In addition, the controller 50 may control the operating frequency (Hz) and capacity of the compressor 13.
Hereinafter, a heat exchanger operating as a condenser according to each situation in a hot water supply and cooling operation mode will be described.
For example, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is a preset reference temperature or less and the cooling load is lower than the preset reference value, it is a situation where a refrigerant cycle for cooling is unnecessary, and only a refrigerant cycle for hot water supply is required. Accordingly, it is controlled so that the first hot water supply expansion valve 33 is opened and the second hot water supply expansion valve 37 is blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is the preset reference temperature or less and the cooling load is lower than the preset reference value, it is a situation where a refrigerant cycle for cooling is unnecessary, and only a refrigerant cycle for hot water supply is required. Therefore, only the hot water supply heat exchanger 32 is controlled to operate as a condenser.
In other words, at this time, the refrigerant flows as illustrated in FIG. 8.
In detail, the hot water supply valve 15 is opened and the discharge valve 16 is blocked. In addition, the first hot water supply expansion valve 33 and the indoor expansion valve 22 are opened, the second hot water supply expansion valve 33 and the outdoor expansion valve 17 are blocked, and only the hot water supply heat exchanger 32 operates as a condenser.
As another example, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is a preset reference temperature or less and the cooling load is higher than a preset reference value, it is a situation where a refrigerant cycle for cooling is also required, and a refrigerant cycle for hot water supply is also required. Accordingly, it is controlled so that the second hot water supply expansion valve 37 is opened and the first hot water supply expansion valve 33 is blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is the reference temperature or less and the cooling load is higher than the preset reference value, it is a situation where a refrigerant cycle for cooling is also required, and a refrigerant cycle for hot water supply is also required. Therefore, both the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are controlled to operate as condensers.
In other words, at this time, the refrigerant flows as illustrated in FIG. 7.
In detail, the hot water supply valve 15 is opened and the discharge valve 16 is blocked. Then, the second hot water supply expansion valve 37, the outdoor expansion valve 17, and the indoor expansion valve 22 are opened, and the first hot water supply expansion valve 33 is blocked, so that the heat exchangers 11 and 32 of the outdoor device 10 and the hot water supply unit 30 operate as condensers, and the heat exchanger 21 of the indoor device 20 operates as an evaporator.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is a preset reference temperature or less and the cooling load is higher than the preset reference value, a refrigerant cycle for cooling is required, and although the refrigerant cycle for the hot water supply is selectively required, it is controlled so that the second hot water supply expansion valve 37 is opened and the first hot water supply expansion valve 33 is blocked.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is the preset reference temperature or more and the cooling load is higher than the preset reference value, a refrigerant cycle for cooling is required, and although the refrigerant cycle for the hot water supply is selectively required, it is controlled so that both the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are operated as condensers.
However, in the hot water supply and cooling operation mode, even if the temperature of the water accommodated in the water tank 31 is the preset reference temperature or more and the cooling load is higher than the preset reference value, it is controlled so that, according to the discharge superheating degree of the compressor 13, the first hot water supply expansion valve 33 may be opened or the second hot water supply expansion valve 37 may be opened.
In detail, in the hot water supply and cooling operation mode, even if the temperature of the water accommodated in the water tank 31 is the preset reference temperature or more and the cooling load is higher than the preset reference value, when the discharge superheating degree of the compressor 13 is smaller than the preset reference superheat, as illustrated in Figure 8, it can be controlled so that only the hot water supply heat exchanger 31 singly operates as a condenser.
In other words, the hot water supply valve 15 is opened and the discharge valve 16 is blocked. In addition, the first hot water supply expansion valve 33 and the indoor expansion valve 22 are opened, the second hot water supply expansion valve 33 and the outdoor expansion valve 17 are blocked, and thus it can be controlled so that only the hot water supply heat exchanger 32 operates as a condenser.
As another example, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is a preset reference temperature or more and the cooling load is lower than a preset reference value, it can be controlled so that only the outdoor heat exchanger 11 operates as a condenser.
In other words, as illustrated in FIG. 3, only the outdoor heat exchanger 11 may singly operate as a condenser so that the hot water supply operation is stopped and the independent cooling operation is performed.
At this time, the hot water supply valve 15 is blocked and the discharge valve 16 is opened. Then, the first hot water supply expansion valve 33 and the second hot water supply expansion valve 37 are blocked, and the outdoor expansion valve 17 and the indoor expansion valve 22 are opened.
In addition, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is the preset reference temperature or more and the cooling load is lower than the preset reference value, the water tank 31 can be heated with a separately provided heater 60 instead the refrigerant cycle.

In the hot water supply and cooling operation mode, a heat exchanger operating as a condenser according to each situation is referred to Table 1 below.

[Table 1]

case	Water Temperature	Cooling Load	Condenser
1	Reference Temperature or less	Reference Value or less	Hot Water Supply Heat Exchanger
2	Reference Temperature or less	Exceeding Reference Value	Hot Water Supply Heat Exchanger and Outdoor Heat Exchanger
3	Exceeding Reference Temperature	Exceeding Reference Value (Exceeding Discharge Super heating Degree Reference)	Hot Water Supply Heat Exchanger and Outdoor Heat Exchanger
4	Exceeding Reference Temperature	Exceeding Reference Value (Discharge Super heating Degree Reference or	Hot Water Supply Heat Exchanger
		less)
5	Exceeding Reference Temperature	Reference Value or less	Outdoor Heat Exchanger

FIG. 10 is a flowchart illustrating a method for controlling a hybrid multi-air conditioning system according to another embodiment of the present disclosure. As described above, the hybrid multi-air conditioning system according to the present disclosure, during cooling and hot water supply operation, according to the water temperature and cooling load, may use the hot water supply heat exchanger 32 or the outdoor heat exchanger 11 as an independent condenser or may use the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 disposed in series together as a condenser.
In addition, a heat exchanger to operate as a condenser may be selected by measuring discharge temperature, condensation temperature, and water temperature through a temperature sensor, a pressure sensor, and the like, and reflecting the operating frequency Hz of the compressor.
In general, since the compressor configures the evaporation temperature according to the required cooling load, and the condensation temperature is relatively low when the cooling load is low, it is difficult to secure discharge superheating degree capable of supplying hot water. This acts as a worse condition as the area of the condenser increases.
In addition, when only the hot water supply heat exchanger 32 is used as a condenser, the condensation temperature can be further increased and the waste heat recovery rate is higher than when the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are used together as the condenser.
However, when the water temperature of the water tank 31 is too high in the cooling low load, because there is a limit to the increase in condensation temperature even if the condenser is reduced by using only the hot water supply heat exchanger 32 as a condenser, it is necessary to heat the water tank 31 by using a separate heater 60 to supply hot water and perform the cooling operation alone.
If the cooling load is large, it is necessary to increase the size of the condenser because the required condensing capacity also increases, and in this case, the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are used together as the condenser.
In addition, since the water temperature in the water tank 31 is relatively higher than the outdoor temperature and the target water temperature is also generally 50 to 60 °C, a series structure in which the water tank 31 is mainly heated by the discharge superheating degree is used.
In addition, when both the water temperature in the water tank 31 and the cooling load are low during cooling and hot water supply operation (for example: water temperature < 40 °C, compressor frequency < 30 Hz), only the hot water supply heat exchanger 32 is singly used as a condenser and thus the condenser waste heat recovery rate can be increased.
In addition, when the cooling load is high during cooling and hot water supply operations, since the condensing capacity is insufficient only with the hot water supply heat exchanger 32, the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are used together as a condenser.
However, when the outdoor temperature is lower than the set temperature, because the discharge superheating degree is secured too low and it is difficult to secure the hot water supply capacity, at this time, only the hot water supply heat exchanger 32 is used as a condenser.
In addition, when the temperature of the water in the water tank 31 is high even though the cooling load is low, hot water supply is impossible.
Therefore, only the outdoor heat exchanger 11 is used as a condenser to perform independent cooling operation, and hot water supply can be performed by a separate heater 60.
Referring to FIG. 10, the hybrid multi-air conditioning system according to the present disclosure selects the heat exchangers 11 and 32 to be used as condensers by calculating the discharge superheating degree with the compressor discharge temperature and condensation temperature during cooling and hot water supply operation and reflecting the information of the calculated discharge superheating degree, the water temperature inside the water tank, and the operating frequency Hz of the compressor
First, after entering the cooling and hot water supply operation mode, the cooling load is determined by comparing the operating frequency of the compressor with a reference value (S11).
For example, if the operating frequency of the compressor 13 is less than 30 Hz, it may be determined that the cooling load is low, and conversely, if the operating frequency of the compressor 13 is 30 Hz or more, it may be determined that the cooling load is high.
In step S11, if the operating frequency of the compressor 13 is less than 30 Hz, it is determined that the cooling load is low, and the temperature of the water in the water tank 31 is detected. (S12)
In step S12, if the water temperature in the water tank 31 is less than the reference temperature, the water temperature in the water tank 31 is low in a low cooling load situation, so the hot water supply heat exchanger 32 is singly used as a condenser. (S15)
In other words, in a situation where the water temperature of the water tank 31 is low as described above, it is determined that it is possible to implement a condenser for cooling and hot water supply only with the hot water supply heat exchanger 32, and in order to increase the condenser waste heat recovery rate, the hot water supply heat exchanger 32 is singly used alone as a condenser.
At this time, the flow of the refrigerant proceeds as illustrated in FIG. 8.
In other words, the hot water supply valve 15 is opened and the discharge valve 16 is closed. In addition, the first hot water supply expansion valve 33 and the indoor expansion valve 22 are opened, the second hot water supply expansion valve 33 and the outdoor expansion valve 17 are closed, and only the hot water supply heat exchanger 32 operates as a condenser.
Meanwhile, in step S12, if the water temperature of the water tank 31 is the reference temperature or more, since the water temperature in the water tank 31 is high in the case of low cooling load, only the outdoor heat exchanger 11 can be controlled to operate as a condenser (S14).
In other words, as illustrated in FIG. 3, the outdoor heat exchanger 11 alone may operate as a condenser so that the hot water supply operation is stopped and the independent cooling operation is performed.
At this time, the hot water supply valve 15 is blocked and the discharge valve 16 is opened. Then, the first hot water supply expansion valve 33 and the second hot water supply expansion valve 37 are blocked, and the outdoor expansion valve 17 and the indoor expansion valve 22 are opened.
As described above, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank 31 is the preset reference temperature or more and when the cooling load is lower than the preset reference value, the water tank 31 is heated by a separately provided heater 60, not by a refrigerant cycle.
In other words, when the hot water supply heat exchanger 32 is used as a condenser in a situation where the cooling load is low and the water temperature in the water tank 31 is the reference temperature or more, it may be difficult to form a normal cycle while reaching the condensation temperature increase limit.
Therefore, in a situation where the cooling load is low and the water temperature in the water tank 31 is the reference temperature or more, it is switched to the single cooling mode, and only the outdoor heat exchanger 11 is singly used as a condenser, and in the case of the water tank 31, hot water is supplied using a separate heater attached to the inside.
On the other hand, in step S11, if the operating frequency of the compressor 13 is 30 Hz or more, it is determined that the cooling load is high, and the discharge temperature of the compressor and the condensation temperature information are used to calculate the discharge superheating degree. (S13)
In the step S13, if the discharge superheating degree is less than the reference temperature, the process proceeds to the step S12.
In addition, in step S12, if the temperature of the water in the water tank 31 is less than the reference temperature, the temperature of the water in the water tank 31 is low in the cooling low load situation, so the hot water supply heat exchanger 32 is used singly as a condenser. (S15)
In addition, in step S12, if the water temperature of the water tank 31 is the reference temperature or more, only the outdoor heat exchanger 11 can be controlled to operate as a condenser (S14).
On the other hand, in step S13, if the discharge superheating degree is the reference temperature or more, the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are used as condensers together (S16).
At this time, the hot water supply valve 15 is opened and the discharge valve 16 is closed. Then, the first hot water supply expansion valve 33 is blocked, and the first hot water supply expansion valve 33, the outdoor expansion valve 17, and the indoor expansion valve 22 are opened.
As described above, when the operation frequency of the compressor is 30 Hz or more in the hot water supply and cooling operation mode, the condensation load increases and thus the size of the condenser may be insufficient only with the water tank. Therefore, both the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are used as condensers.
However, at this time, if the discharge superheating degree is not secured 5 °C or more (if outdoor temperature is too low), after checking whether the water temperature is 40 °C or less, if it is 40 °C or less, the hot water supply heat exchanger 32 is operated singly through valve control use as a condenser.
If the water temperature is 40 °C or more, the outdoor heat exchanger (11) is used alone as a condenser, and the water in the water tank (31) is heated with a separate heater because the risk of high pressure limitation is high at the cooling load of 30 Hz or higher.
Conversely, if the discharge superheating degree of 5 °C or higher can be secured when the compressor is 30 Hz or higher, the hot water supply heat exchanger 32 and the outdoor heat exchanger 11 are continuously used as condensers.
In the above method, values of the operating frequency of the compressor, which is the standard for determining the cooling load, the water temperature which is the standard, and the value of the discharge superheating degree which is the standard may be changed according to circumstances.
According to the present disclosure as described above, there is an advantage in that a heat exchanger for heating a water tank and a heat exchanger for an outdoor device are disposed in series, so that hot water supply performance can be secured as the refrigerant flow rate in the discharge superheating degree section increases.
In addition, in the case of a heat exchanger for an outdoor device, supercooling is secured, so that cycles can be implemented more stably and the condensation temperature can be lowered.
In addition, there is an advantage that only the heat exchanger for the water tank can be operated as a condenser or only the heat exchanger for the outdoor device can be operated as a condenser.
In addition, there is an advantage in that the heat exchanger for the water tank and the heat exchanger for the outdoor device can simultaneously operate as condensers.
In other words, in the case of the present disclosure, there is an advantage in that the condenser can be selected and operated according to each situation.
In addition, there is an advantage in that, in the case of the present disclosure, during cooling and hot water operation, when the cooling load and water temperature are high, the water tank heat exchanger and the outdoor device heat exchanger are disposed in series to be used as condensers at the same time, and, when the cooling load and water temperature are low, waste heat recovery efficiency can be further increased by using only the water tank-side heat exchanger as a condenser.
In addition, during cooling and hot water supply operation, the condensation temperature is lowered to increase the cooling performance and the efficiency of hot water supply, and thus it is advantageous to prevent damage to the compressor, and there is an advantage in that the waste heat recovery rate and efficiency of hot water supply can increase under low load conditions or low water temperature in the water tank.
In addition, there is an advantage in that heat exchange efficiency is improved by directly exchanging heat between the refrigerant and water by winding a coil capable of exchanging heat between the refrigerant and water around the water tank.
In addition, there is an advantage in that the inflow of abnormal refrigerant can be prevented by controlling the optimum degree of supercooling degree by adjusting the opening degrees of the first hot water supply expansion valve and the outdoor expansion valve without installing a separate receiver.
In addition, there is an advantage in that simultaneous operation of hot water supply and cooling as well as operation of hot water supply and heating are possible.

Claims

A hybrid multi-air conditioning system (100) comprising:
a hot water supply unit (30) including a hot water supply heat exchanger (32) for exchanging heat between a refrigerant and water accommodated in a water tank (31) and a first hot water supply expansion valve (33) for blocking or flowing the refrigerant condensed from the hot water supply heat exchanger (32);

at least one indoor device (20) installed indoors and including an indoor heat exchanger (21) and an indoor expansion valve (22);

an outdoor device (10) connected to the indoor device (20) and the hot water supply unit (30) through a refrigerant pipe and including an outdoor heat exchanger (11), a compressor (13), and an outdoor expansion valve (17);

a second hot water supply discharge pipe (36) having one side branched from a first hot water supply discharge pipe (35) connecting the hot water supply heat exchanger (32) and the indoor heat exchanger (21) and the other side joining a first discharge pipe (43) connecting the compressor (13) and the outdoor heat exchanger (11); and

a second hot water supply expansion valve (37) installed on the second hot water supply discharge pipe (36).
The hybrid multi-air conditioning system (100) of claim 1, further comprising:
at least one of a first temperature sensor (38) installed to detect the water temperature in the water tank (31) and a second temperature sensor (47) installed at a rear end of the compressor (13).
The hybrid multi-air conditioning system (100) of claim 1 or 2, further comprising:
a first pressure sensor (48) installed at the rear end of the compressor (13).
The hybrid multi-air conditioning system (100) according to any one of claims 1 to 3,
wherein the hot water supply heat exchanger (32) winds the outer wall of the water tank (31) in a coil form and is configured to exchange heat between the refrigerant and water while the refrigerant flows into the inside of the hot water supply heat exchanger (32).
The hybrid multi-air conditioning system (100) according to any one of claims 1 to 4,
wherein the outdoor device (10) includes:
a hot water supply valve (15) for flowing the compressed refrigerant from the compressor (13) to the hot water supply unit (30);

a discharge valve (16) for flowing the compressed refrigerant from the compressor (13) to the outdoor heat exchanger (11) or the indoor heat exchanger (21); and

a four-way valve (14) for transferring the refrigerant passing through the discharge valve (16) to the outdoor heat exchanger (11) or to the indoor heat exchanger (21).
The hybrid multi-air conditioning system (100) according to any one of claims 1 to 5,
wherein a plurality of indoor heat exchangers (21) is provided, and each indoor heat exchanger (21) is connected in parallel.
The hybrid multi-air conditioning system (100) according to any one of claims 1 to 6,
wherein the first hot water supply expansion valve (33) is installed at a rear end of a branch point of the second hot water supply discharge pipe (36) in the first hot water supply discharge pipe (33).
The hybrid multi-air conditioning system (100) of claim 7,
wherein, in the hot water supply and cooling operation mode, either the hot water supply heat exchanger (32) or the outdoor heat exchanger (11) operates as a condenser, or the hot water supply heat exchanger (32) and the outdoor heat exchanger (11) operate as a condenser.
The hybrid multi-air conditioning system (100) of claim 7 or 8,
wherein, in the hot water supply and cooling operation mode, one of the first hot water supply expansion valve (33) and the second hot water supply expansion valve (37) is opened and the other is blocked.
The hybrid multi-air conditioning system (100) of claim 9,
wherein, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank (31) is the reference temperature or less and when the cooling load is lower than the reference value, the first hot water supply expansion valve (33) is opened and the second hot water supply expansion valve (37) is blocked.
The hybrid multi-air conditioning system (100) of claim 9,
wherein, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank (31) is the reference temperature or less and, when the cooling load is lower than the reference value, only the hot water supply heat exchanger (32) operates as a condenser.
The hybrid multi-air conditioning system (100) of claim 9,
wherein, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank (31) is the reference temperature or less and, when the cooling load is higher than the reference value, the second hot water supply expansion valve (33) is opened and the first hot water supply expansion valve (37) is blocked; and

wherein the hot water supply heat exchanger (32) and the outdoor heat exchanger (11) operate as condensers.
The hybrid multi-air conditioning system (100) of claim 9,
wherein, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank (31) is the reference temperature or more and, when the cooling load is higher than the reference value, the second hot water supply expansion valve (33) is opened and the first hot water supply expansion valve (37) is blocked; and

wherein the hot water supply heat exchanger (32) and the outdoor heat exchanger (11) operate as condensers.
The hybrid multi-air conditioning system (100) of claim 9,
wherein, in the hot water supply and cooling operation mode, even if the temperature of the water accommodated in the water tank (31) is the reference temperature or more and, when the cooling load is higher than the reference value, the first hot water supply expansion valve (37) is opened or the second hot water supply expansion valve (33) is opened according to the discharge the superheating degree of the compressor (13).
The hybrid multi-air conditioning system (100) of claim 8,
wherein, in the hot water supply and cooling operation mode, when the temperature of the water accommodated in the water tank (31) is the reference temperature or more and, when the cooling load is lower than the reference value, only the outdoor heat exchanger (11) operates as a condenser; or

wherein the water tank (31) is heated by a separate heater (60).